


<S 






LIBRARY OF CONGRESS 



002 861 299 0< 



Hollinger Corp. 
P H8.5 



AMERICAN FISHES IN ITALY 

J- 

By Guiseppe Besana 

President Lariana Section, Lombard y Society oj Fisheries and Aquiculture 

Paper presented before the Fourth International Fishery Congress 
held at Washington, U. S. A., September 22 to 26, 1908 

BULLETIN OF THE BUREAU OF FISHERIES :::::: VOL. XXVIII, P. 947-954 
Document No. 695 ::::::::::: : : : : Issued April, 1910 



947 



£> 



.^ 



tb- 



<&■ 



APR 15 1310 



AMERICAN FISHES IN ITALY. 
■*. 

By GUISEPPE BESANA, 
President Lariana Section, Lombardy Society oj Fislieries and Aquicullure. 

J* 

[Translated from the German.] 

REARING IN ARTIFICIAL PONDS. 

In the small ponds of the Piseicoltura Borghi at Varano-Borghi, opened in 
1907, were produced at first mostly fry and yearling fishes for stocking purposes. 
But as the plants were without results, the ponds were increased in number 
and the rearing of table fishes was undertaken, including attempts to cultivate 
American trouts and salmon, namely, Salmo irideus, Oncorhynchus tschawytscha, 
and Salvelinus fontinalis. Experiments were made also with Salmo clarkii, 
crossing it with the rainbow trout. 

Of these fishes, at the present time only the rainbow trout is being culti- 
vated. The quinnat grew extraordinarily fast during the first year and without 
losses, reaching a size for table use during that one year; but the flesh was not 
yet firm nor of good flavor. The growth was still good during the second year, 
but in the third year there remained but very few of the fish, and they were 
thin and for the most part died during the period of spawning. The quinnat 
presented another disadvantage during the second year, being so delicate that 
when fished out to be transferred to other ponds, in spite of the great care 
taken, a great number of them died. The brook trout grew very well during 
the first year, markedly less during the second year, still less during the third, 
while the mortality continually increased. Compared with the European sal- 
monoids the best results were obtained with the rainbow trout. In the second 
summer these trout reached the size of table fishes, weighing 150 to 200 grams, 
and the flesh had a good flavor. They endure transportation well, and readily 
take artificial food. We know of no other salmonoids so well adapted to culture 
in ponds. The few experiments in crossing the irideus with the clarkii trout did 
not encourge further effort, as the growth of the hybrid is far inferior to that 
of irideus. 

949 



950 



BULLETIN OF THE BUREAU OF FISHERIES. 



PLANTS IN LAKE MANATE. 

The area of this lake is 240 hectares; greatest depth, 37 meters; plankton 
abundant; vegetation scant; maximum temperature of water, 8° C. at the 
bottom, 24 C. at the surface; minimum temperature, 8° C. at the bottom, 
o° C. at the surface. The native fishes of this lake are, in the order of their 
abundance, river perch, tench, roach, pike, bleak, eel, and burbot. Tables 1, 
11, hi, and iv show the plants of the introduced fishes and the catch. Table V 
gives the catch for 1907. 

Table I. — Rainbow Trout (Salmo irideus). 



1S97 
1898 
1899 
1899 
1900 
1901 
1901 
1902 
1903 
1904 



Size or age of fish planted. 



Fishes 2 years old 

Small fry 

Yearlings 

Fry 2 months old 

Fry 2 months old 

Yearlings 

Fishes weighing 400 grams each 

Fry 2 months old 

Small fry 

Small fry 

Total 



Number 
planted. 



800 

4. 130 

8.6:8 

676 

1, 400 

300 

21 

4.500 

10. 000 

10. 000 



Number 
caught. 



Weight 
of catch. 



Kilograms 



9. 800 



Table II. — Brook Trout (Salvelinus fontinalis). 



1903 
j 903 
1903 
1904 
1905 



Size or age of fish planted. 



Fry 2 months old 

Yearlings 

Fish weighing 200 grams each 

Small fry 

Yearlings 

Total 



Number 
planted 



2 . 240 
80 

150 
2. 500 

518 



5.488 



Number 
caught. 



Weight 
of catch. 



Kilograms. 



Table III. — Black Bass (Micropterus salmoides). 



Size or age of fish planted. 



Number 
planted. 



Number 
caught. 



Weight 
of catch. 



1897- 
1897- 
1897- 
1899- 
1901. 
1902. 
1903- 
1904- 
190s- 
1906. 
1907- 



Yearlings 

Fish 2 years old. 
Fish 3 years old- 



500 

86 

6 



30 
76 

226 

163 
372 
343 
803 

241 

.254 



Kilograms . 



7» 
217 
196. 
284 
246 
368 
147 



AMERICAN FISHES IN ITALY. 

Table IV. — Sunpish (Lepomis auritus). 



951 



Year. 


Number 
of fish 
planted. 


A verage 

weight when 

planted. 


Weight 
of catch. 


1901 . __ __ _ _ _ __ 


140 
66 
91 


Gravis. 

30 
45 
50 


Kilograms . 


1 90 1 _ _ _ _____ . 


















164. 60 
249. 20 
300. 10 
302. 70 


























Total _ ___ 


297 




1. i37 40 







Table V. — Total Catch in Lake Manate in 1907. 



Species. 


Number. 


Weight. 




618 


Kilograms. 
706. 70 
562- 80 






107 
24 
53 




14. 70 

46.50 

302. 70 

302. 70 












241 
4 










Total... _ _ _ - . 




2, 107. 20 







Failures were noticeable with the salmonoids. I must add, however, that 
I have had similarly negative results with European salmonoids. It was only 
in the beginning of this year that there were caught 100 Coregonus marcene, 
weighing from 0.50 to 2 kilograms. Fry of this species had been introduced, 
and a large individual was seen only here and there. No fry had been planted 
in the lake for four years, and the smaller fishes which were caught, weighing 
800 grams, must, have been bred from fishes that had spawned in the lake. 

The sunfish did not increase greatly in this lake; the catches are insignifi- 
cant and have never exceeded 300 kilograms yearly, i. e., somewhat over 
1 kilogram per hectare. 

I had built great hope on the black bass. Young Micropterus were seen 
everywhere during the first years. The first catch was made only four years 
after their introduction, and it increased to 368 kilograms. During the last 
year, however, it fell to one-half of this quantity, and the present year will 
show still poorer results. When the black bass was introduced there were 
quantities of bleak in the lake, and this fish was not caught at all. At the 
present time it has entirely disappeared. 

Lake Manate yields at present, as formerly, 3,000 to 5,000 kilograms of fish 
yearly. No benefit was derived from the introduction of new species of fishes, 



952 BULLETIN OF THE BUREAU OF FISHERIES. 

but perhaps even some disadvantage. Micropterus, which bring a higher price, 
have disappeared, as have also the river perch and the pike, probably on account 
of a lack of small fishes for food. The tench and the roach (Lcuciscus erythro- 
phtalmus) are the only ones that remain. 

How to provide new food is the present difficult problem, which, after the 
failure with the sunfish, will scarcely find easy solution with present experience. 

PLANTS IN LAKE VARANO. 

Area of this lake, 360 hectares; greatest depth, 7 meters; much plankton, 
very rich vegetation; maximum temperature of the water, 24 C. at the surface, 
24 C. at the bottom; minimum temperature, o° C. at the surface, 6° C. at the 
bottom. 

The species of fish contained in the lake are, in the order of their abundance, 
sunfish, river perch, tench, bleak, black bass, eel, zander, mirror carp, and pike. 
The sunfish and black bass, also the zander and the carp, were introduced in 
this lake. 

The results obtained with the American fishes here are marvelous, especially 
with the sunfish, as two other lakes communicating with Lake Varano are over- 
stocked with sunfish. It is scarcely possible to notice any effect on the other 
kinds of fishes, except that the pike has grown scarcer and the bleak has 
disappeared. The river perch is much fatter and grows much more rapidly 
than before. 

The plants of introduced fishes, together with subsequent catches, are shown 
in tables vi and vii. The yearly output of fish of all kinds, amounting, formerly 
to 170 tons, has increased to 300 and more tons. Table vm gives the total 
catch for 1907, which is exceedingly good, amounting to almost 90 kilograms per 

hectare. . 

Table VI. — Sunfish (Lepomis aukitus). 

[Eiyhty-three 3-year old brood fishes introduced in 19C0.] 



1901 . 
1902. 
1903- 
1904- 
1905- 
1906. 

Iy07_ 



Total. 



Weight of 
catch. 



Kilograms 
682 
1. 919 
5. 845 
S.958 
7.456 
5.99o 
12. 811 



40.665.3 



AMERICAN FISHES IN ITALY. 
Table VII. — Black Bass (Micropterus salmoides). 



953 





Fish introduced. 


Number 
caught. 


Weight of 
catch. 


Year. 


Number. 


Size or age. 


Average 
weight. 




8 
I . ooo 

21 

6 




Grams. 
560 




Kilograms. 


IOOO 












860 

500 


















859 
3. 193 
2. 183 
8.941 
5.896 












2. 204. 90 




















2. 987. 20 
























21. 872 















Table VIII. — Total Catch in Lake Varano in 1907. 



Species. 



Tench (Tinea vulgaris) 

River perch (Perca fluviatilis) 

Small eels (Anguilla vulgaris) 

Large eels (Anguilla vulgaris) 

Pike (Esox lucius) 

Bleak ( Alburnus alborella) 

Sunfish ( Lepomis auritus) 

Black bass (Micropterus salmoides). 

Carp (Cyprinus carpio) 

Zander (Lucioperca sandra) 



Total . 



Number. 



1 . 066 
894 
224 



5.896 

52 

219 



Weight. 



Kilograms. 

3.634.70 

7. 568. 10 
280. 50 
4S7-30 
232. 10 

2. 626. 60 
12, 81 1 . 40 

2.345 70 
280. 30 
407. 70 



30,644. 40 



I was criticised for introducing the sunfish, but I believe that I do not 
deserve it. The sunfish is of much better flavor than the ordinary bleak. 
Delicious steaks can be cut out of the larger of them, and the fish bring a good 
price where better known. They are also a very good food for the carnivorous 
fishes in the lake. They increase in an extraordinary manner in shallow lakes 
and must be fished out diligently. They do not reach any importance in deeper 
lakes and in consequence can not have any effect. In lakes where there are no 
salmonoids the sunfish should be an excellent item of popular, food. The average 
weight of the fish caught is 100 grams, which is reached in three years, but we 
have caught individuals weighing 400 grams. Another advantage is that 
except when the lake is frozen it is always possible to catch more or less sunfish, 
a thing which is of great importance to the fisherman. The long spawning 
season, lasting from May until the middle of August, offers the advantage that, 
as the sunfish do not grow during the winter, there is present through almost 
the entire year a quantity of small fishes to constitute a food for the predator}' 
species. If the sunfish now and then eats other small fry, it does not consume 
dangerously great quantities. That it does not eat spawn is well established. 
The fish should be of great value in Italy in swampy waters, where it thrives 



"g" 002 "861 299 * 



954 BULLETIN OF THE BUREAU OF FISHERIES. 



very well and can stand great heat and great cold. While Lake Manate, which 
is of far greater depth, produced only a little more than i kilogram per hectare, 
the shallow Lake Varano with its swampy bottom produced 35 kilograms of 
sunfish per hectare during the past year. 

The black bass also flourished in this lake (table vn) , yielding somewhat 
less than 10 kilograms per hectare. The fishing is very irregular and uncertain, 
however, some 100 kilograms being caught one day, while on the next not one 
fish maybe found. The black bass can be transported safely alive. Its flesh is 
boneless and very palatable, but its plump shape and big head make its sale 
difficult. There is much around the head that can be eaten, but most people 
prefer the zander. The growth of the black bass is markedly greater than that 
of the river perch. While the latter seldom reaches 1 kilogram and this in some 
eight or nine years, the black bass reaches this weight in three years. It 
increased in number considerably during the first years, but later, when there 
were many large individuals, these ate up many of the smaller of their species. 
It has no effect whatever on the other fishes in the lake, except Alburnus alborella, 
which it has eaten up entirely. I certainly prefer the zander, but it can not be 
introduced into all waters, while the black bass will thrive anywhere. 

I have also introduced the black bass in small lakes with great success and 
at a small cost. In order to make this success lasting, however, it is necessary 
to introduce the sunfish at the same time. The small bleak is soon eaten up 
by the black bass, the sunfish alone, on account of its enormously prolific 
propagation, being able to withstand and keep ahead of this terrible devourer. 

On account of the defective organization on the part of our government 
in respect to fisheries, it is impossible for me to report on the introduction of 
rainbow trout in public waters, or on catfish, black bass, and sunfish in 
other lakes. It may be seen, however, from the above reports, that great 
advantages may be reaped from the introduction of these and other American 
fishes. 



LIBRARY OF CONGRESS 

mill i! nun 



002 861 299 



He 



LIBRARY OF CONGRESS 



002 861 299 01 



Hollinger Corp. 
P H8.5 



